Where does “Erythraean Sea” come from?

Erythraean Sea (English) comes from Latin Erythraeum mare, from Ancient Greek Ἐρυθρὰ Θάλασσα.

Ancestry of “Erythraean Sea”, step by step

Step	Language	Word	Meaning
1	Latin	Erythraeum mare	—
2	Ancient Greek	Ἐρυθρὰ Θάλασσα	—

Erythraean Sea — Etymology, Origin & Word History | Etymology Explorer